EP0592209A1 - Verfahren zur Basisstationensynchronisierung und Funkkommunikationssystem mit Anwendung des Verfahrens - Google Patents

Verfahren zur Basisstationensynchronisierung und Funkkommunikationssystem mit Anwendung des Verfahrens Download PDF

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Publication number
EP0592209A1
EP0592209A1 EP93307951A EP93307951A EP0592209A1 EP 0592209 A1 EP0592209 A1 EP 0592209A1 EP 93307951 A EP93307951 A EP 93307951A EP 93307951 A EP93307951 A EP 93307951A EP 0592209 A1 EP0592209 A1 EP 0592209A1
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European Patent Office
Prior art keywords
radio base
base station
synchronization
station
state
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EP93307951A
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English (en)
French (fr)
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Keishi c/o Nippon Steel Corporation Matsuno
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Nippon Steel Corp
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Nippon Steel Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/65—Arrangements characterised by transmission systems for broadcast
    • H04H20/67—Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2662—Arrangements for Wireless System Synchronisation
    • H04B7/2668—Arrangements for Wireless Code-Division Multiple Access [CDMA] System Synchronisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2662—Arrangements for Wireless System Synchronisation
    • H04B7/2671—Arrangements for Wireless Time-Division Multiple Access [TDMA] System Synchronisation
    • H04B7/2678—Time synchronisation
    • H04B7/2687—Inter base stations synchronisation
    • H04B7/269—Master/slave synchronisation

Definitions

  • the present invention relates to a method of establishing inter-base-station synchronization in a mobile radio communication system operated in a time division multiple access (TDMA) mode or a code division multiple access (CDMA) mode and a mobile radio communication system using the method.
  • TDMA time division multiple access
  • CDMA code division multiple access
  • a mobile radio communication system in particular in a mobile telephone system for automobiles, to gradually reduce service areas of respective radio base stations forming conventional large or medium zones, e.g., to areas each having a radius of 5 Km to 3 Km.
  • the effective utilization of frequencies by forming smaller zones is useful especially in a personal radio communication system which is planned to be put into practical use.
  • a small zone system is studied in which each zone has an area of several hundred meters to several ten meters in the radius which is called a microcell or a picocell, as disclosed in the Transactions of the Institute of Electronics and Information Communication Engineers in Japan (B), J71-B, No. 5, May 1988 pp. 633 ⁇ 639.
  • a TDMA system When a TDMA system is adopted in such a multizone, it is required to establish synchronization between frames used by respective radio base stations provided in contiguous zones forming a multizone, in order to assure functions of detecting and/or avoiding interference, that is, to cause the radio base station in each zone to perform telephone communication with a mobile station located in that zone at the same frame timing as that at which the adjacent base station performs its telephone communication, as disclosed in "Autonomous Decentralized Inter-Base-Station Synchronization for TDMA Microcellular Systems" Akaiwa et al IEEE 1991 pp. 257 ⁇ 262. As to the necessity of synchronization between radio base stations, it has been reported that the efficiency in using the slots is lowered by 25% to 30% in an asynchronous condition as compared with that in a synchronous condition.
  • the PHP is applied to indoor mobile terminals in offices or homes and outdoor mobile terminals for public telephone communication.
  • a business cordless telephone system called a behind PBX is introduced and the synchronization among respective radio base stations is established based on a command from the PBX.
  • PBX business cordless telephone system
  • a method of establishing synchronization between radio base stations in a mobile radio communication system comprises the steps of: including, in a control signal transmitted at a predetermined time interval from each of the radio base stations, synchronization establishing information indicating whether the radio base station is in a first state in which synchronization has been established between the radio base station and any other one of the radio base stations or in a second state in which the synchronization has not been established as yet; determining, in a receiving radio base station, which is one of the radio base stations and has received the control signal transmitted from a transmitting radio base station, which is any other one of the base stations, and when said receiving radio base station is in the second state, whether the synchronization establishing information included in the received control signal indicates the first state or the second state; establishing, in the receiving radio base station, synchronization with the transmitting radio base station, when it is determined that the synchronization establishing information included in the received control signal indicates the first state; and setting, after establishing the synchronization with the transmitting radio base station,
  • each of the radio base stations comprises: means for including, in a control signal transmitted at a predetermined time interval from the own radio base station, synchronization establishing information indicating whether the own radio base station is in a first state in which synchronization has been established between the own radio base station and any other one of the radio base stations or in a second state in which the synchronization has not been established as yet; means operative, when the own radio base station is a receiving radio base station which has received the control signal transmitted from a transmitting radio base station which is any other one of the radio base stations, for determining whether the synchronization establishing information included in the received control signal indicates the first state or the second state; means operative, when the radio base station is the receiving radio base station and in the second state, for establishing synchronization with the transmitting radio base station, when it is determined that the synchronization establishing information included in the received control signal indicates the first state; and means for setting, after establishing synchron
  • each radio base station transmits a control signal such as a broadcast signal intermittently at a predetermined time interval within an allocated zone.
  • the broadcast signal includes, for example, a transmitter identification signal for identifying the transmitting base station so that a mobile station located in a zone covered by the transmitting radio base station may confirm the present zone and a signal indicating various specifications employed.
  • the radio base station which transmits the control signal includes synchronization establishing information indicating whether the base station has established synchronization with another radio base station or not in the control signal.
  • the base station which has received the control signals and has not established synchronization with any other base station, establishes, when the synchronization establishing information included in the received control signal indicates that synchronization has been established, synchronization with the base station which has transmitted the control signal and sets the synchronization establishing information included in the control signal transmitted by itself to a state indicating that synchronization has been established.
  • each radio base station can establish synchronization with another base station by autonomous-control without depending on a higher rank station.
  • a mobile radio communication system for example, service zones covered by a plurality of radio base stations 201 to 205, respectively, overlap one another so as to form a multizone as shown in Fig. 8. Similarly, service zones covered by a plurality of radio base stations 207 to 213, respectively, also overlap one another so as to form another multizone.
  • the radio base stations 201 to 205 are connected to a telephone exchange or a control station 301 through wire transmission lines 26, and communication between mobile stations located in service zones of different base stations is performed through the control station 301.
  • radio base stations 207 to 213 are also connected to a telephone exchange or a control station 302 through wire transmission lines 26, and communication between mobile stations located in service zones of different base stations is performed through the control station 302.
  • the control stations 301 and 302 are connected further to a higher rank telephone exchange 110, and, for example, communication between a mobile station located in the service zone of the base station 201 and a mobile station located in the service zone of the base station 207 is performed through the control stations 301 and 302 and the higher rank telephone exchange 110.
  • Fig. 2 typically shows structure of one of the base stations and the higher rank control station in a mobile radio communication system as described above.
  • a mobile radio communication system is provided with a base station (BS) 20, a mobile radio communication control station (MCC) 30 and mobile stations (MSs) 41, 42, etc.
  • Radio communications are set between mobile stations 41, 42, ... and the radio base station 20 through antennas 61, 62, ... provided to the mobile stations 41, 42, ... and an antenna 70 provided to the radio base station 20.
  • the mobile radio communication control station 30 is installed as a part of a private branch exchange, and is connected to the radio base station 20 through wire transmission lines 26 and 29.
  • a received signal received by the antenna 70 of the radio base station 20 is inputted to a multiplexer (MUX) 23 through a common amplifier (AMP) 21 and a modulator-demodulator (MDE) 22.
  • MUX multiplexer
  • AMP common amplifier
  • MDE modulator-demodulator
  • Communication between each of a plurality of base stations included in one multizone and the higher rank control station is performed for effective use of the transmission lines 26 by the TDMA system for instance by using a multiplex signal, which is obtained by allocating a plurality of slots provided in a communication signal of a predetermined digital form to the respective base stations, and by writing information to be communicated in the slots allocated to that base station.
  • the multiplexer 23 stores once a signal received by the base station from a mobile station located in its service zone and writes the signal in the allocated slots of the communication signal thereby converting the signal into a multiplex signal.
  • the converted multiplex signal is transferred to the multiplexer (MUX) 32 in the control station 30 through the transmission line 26.
  • the multiplex signal transferred to the multiplexer 32 is reconverted to the original signal before multiplexing, and is transferred to a mobile radio communication exchange (MCX) 33 through a speech processing equipment (SPE) 31.
  • An output signal line 34 of the mobile radio communication exchange (MCX) 33 is connected to a public switched telephone network (PSTN).
  • PSTN public switched telephone network
  • a transmitted signal to be transmitted to a mobile station is inputted from the public switched telephone network to the mobile communication control station 30 and transferred to the base station 20 in a reverse direction through the respective equipments described above, and transmitted to a destined one of the mobile stations 41, 42, ... from the antenna 70 after being processed for conversion by the respective equipments similarly to the above.
  • the modulator-demodulator 22 and the mobile radio communication exchange 33 are controlled for various processings including synchronization by a base station control equipment (BCE) 24 through bidirectional digital signal lines 27 and 29.
  • BCE base station control equipment
  • Various signals indispensable for maintenance, monitoring or the like are gathered or transmitted bidirectionally also through the digital signal lines 27 and 29 and a maintenance and monitoring signal line 35 as a data base of the public switched telephone network or the like, as occasion demands.
  • the base station control equipment (BCE) 24 includes a synchronization establishment control equipment which is described later with reference to Fig. 4 and performs, based on the received control signal or the broadcast signal, synchronization processing for making the timing of the broadcast signal transmitted from its own station coincident with the timing of the received broadcast signal.
  • Fig. 3 is a block diagram showing a modification of a mobile radio communication system of an embodiment according to the present invention. This modification is suitable for a small-scale radio base station, and the mobile radio communication control station 30 is installed in a subscriber's circuit of a local switchboard connected to a public switched telephone network.
  • the same components as those in Fig. 2 are designated by the same reference numerals, and the descriptions thereof are omitted.
  • a control signal line 28 for connecting between the base station control equipment 36 and the synchronization establishment control equipment 25 is newly required, but simplification, miniaturization and cost reduction of a radio base station which are the subjects of a microzone system becomes possible, thus making its practical use easy.
  • a plurality of signal lines 26 and control signal lines 28, as shown in Fig. 3, are used for a plurality of base stations, respectively.
  • Fig. 4 is a block diagram showing an example of a structure of the synchronization establishment control equipment 25.
  • a reference numeral 51 represents a controller, 51-2 a memory, 52 a digital correlator, 53 a comparison and decision circuit, 54 a transmission timing control memory, 55 a synchronization lag time correction circuit, and 56 a data array circuit.
  • This synchronization establishment control equipment 25 performs, based on the broadcast signal outputted to the signal line 27 from the modulator-demodulator unit 22 shown in Fig. 3, synchronization for making the transmitting timing of the broadcast signal as transmitted from its own station coincident with the transmitting timing of this received broadcast signal.
  • the controller 51 also performs write of synchronization establishing information into the transmitting broadcast signal and alteration thereof, and further stores the data of identification of the synchronized base station and the propagation delay time in the memory 51-2.
  • the broadcast signal utilized for synchronization between the radio base stations is a digital control signal of a predetermined format transmitted intermittently at a predetermined constant period of approximately several seconds from each radio base station for notifying each of the mobile stations in its service zone of the zone where the mobile station is located.
  • Fig. 5 shows an example of a structure of physical slots of the broadcast signal.
  • SS represents bits of a start symbol showing the head of the broadcast signal
  • R represents bits of response ramp time for allowing each mobile station to receive SS surely
  • PR represents bits of a preamble used for synchronization of data bits of the broadcast signal
  • UW represents unique word bits used for detecting frame synchronization
  • CI represents bits indicatng a channel used for data communication of the broadcast signal
  • SI represents bits indicating a transmitter identification code for identifying a transmitting base station
  • BCCH represents bits indicating various broadcast messages
  • CRC represents bits of a cyclic redundancy check code used for checking an error
  • G represents guard bits for correcting timing shift between slots, and all of them are well known.
  • the transmitter identification code SI further includes a system calling code or an enterprise calling code EID indicating identification of the system or enterprise relating to the broadcast signal and an additional ID.
  • a one-bit signal SE indicating the synchronization establishing state is included in the ID bits.
  • a synchronization establishment control processing utilizing the received broadcast signal which is executed by the synchronization establishment control equipment 25 shown in Fig. 4, will be described with reference to the flow chart shown in Fig. 1.
  • the processing shown in this flow chart may be executed by means of a microcomputer incorporated in the controller 51 shown in Fig. 4.
  • the synchronization establishment control equipment 25 Upon application of a power supply to the system or detection of deviation of synchronization with another radio base station by a comparison and decision circuit 53 as described later during operation, the synchronization establishment control equipment 25 starts synchronization establishment control processing shown in the flow chart of Fig. 1.
  • the controller 51 first inverts a self-contained flip-flop for holding synchronization establishing information of one bit indicating whether the station is in a synchronization establishing state with another radio base station or not from "1" (ON) to "0" (OFF) (step 1), and waits for reception of the broadcast signal (step 2).
  • the controller 51 which has received notification that the broadcast signal is received checks the contents of the transmitter identification code included in the received broadcast signal (step 3), and judges the synchronization establishing information included therein (step 4).
  • This synchronization establishing information is set to ON ("1") when the radio base station which has transmitted the received broadcast signal is in a synchronization established state with another radio base station, and set to OFF ("0") when the station is in a synchronization non-established state.
  • the controller 51 executes synchronization with the radio base station which has transmitted the received broadcast signal and is in the synchronization established state (step 6).
  • the synchronization in the step 6 is executed by computing a lag time between a transmission timing of the broadcast signal from the own station stored in its station transmission timing control memory 54 and a reception timing of the received broadcast signal, setting a corrected value of the lag time in a synchronization lag time correction circuit 55, and altering control data in the station transmission timing control memory 54 so as to cause the transmission timing of the own station to substantially coincide with the transmission timing of the transmitting base station from which the received broadcast signal has been transmitted.
  • a propagation delay time, or an accurate distance to the transmitting radio base station is required in order to determine the transmission timing of the transmitting base station accurately based on the reception timing of the received broadcast signal.
  • the transmission timing of the own radio base station is corrected by, for example, 0.33 ⁇ s equal to the propagation delay time for the average radius thereby making the transmission timing of the own base station coincident with the transmission timing of the transmitting base station.
  • the controller 51 inverts the synchronization establishing information provided by the self-contained flip-flop from OFF ("0") to ON ("1") thus concluding synchronization establishment processing (step 7).
  • propagation delay time it may also be arranged such that propagation time of radiowave between the radio base station and each of the other existing base stations is measured or calculated from the positional relationship between them at a time when the radio base station is installed and is stored in a memory 51-2 connected to the controller 51, and the propagation delay time with respect to the transmitting base station of the received control signal is read out of the memory and used when synchronization processing is performed in the step 6.
  • propagation time of radiowave between the radio base station and each of the other existing base stations is measured or calculated from the positional relationship between them at a time when the radio base station is installed and is stored in a memory 51-2 connected to the controller 51, and the propagation delay time with respect to the transmitting base station of the received control signal is read out of the memory and used when synchronization processing is performed in the step 6.
  • the efficiency of frequency utilization of broadcast signal should be low if the measurement of the propagation delay time of radiowave in the step 6 in Fig. 1 is repeated. Accordingly, the step 5 and the steps thereafter are modified as shown in Fig. 1B.
  • step 6 shown in Fig. 1 when measurement of the propagation delay time of radiowave between base stations is completed, the measured propagation time delay is stored in the memory 51-2 connected to the controller 51 shown in Fig. 4 together with the information for specifying the transmitting base station.
  • step 5 for discriminating the synchronization establishing information when the synchronization establishing information of the transmitting base station is in an ON-state, the controller 51 investigates whether the own radio base station has ever established synchronization with the transmitting base station previously or not by reading the information in the memory 51-2 (step 14). When no information on the base station has been stored in the memory 51-2, the controller 51 executes synchronization in the step 6 similarly to Fig. 1.
  • the controller 51 When the information on the transmitting base station has been stored in the memory 51-2, the controller 51 reads the radiowave propagation delay time out of the memory 51-2 (step 16), and executes synchronization by correcting the transmission timing of the own base station by the propagation delay time (step 18) so that the starting time in transmission of the control signal from the own base station coincides with the starting time in transmission of the control signal from the transmitting base station. Then, the controller 51 sets the synchronization establishing information to ON without measuring the propagation time again (step 7). With the above, it becomes unnecessary to always measure the radiowave propagation time at execution of synchronization like the step 6 in Fig. 1. This is based on such an idea that the power supply is interruptted sometimes after installation of the base station, but it is seldom that the installed location is altered greatly so that the propagation delay time must be changed.
  • the controller 51 determines that no other radio base station forms a multizone with the own radio base station and shifts the process to a step 10. Further, when it is detected that, although another radio base station forms a multi-zone with the own station, the other radio base station is also in a synchronization non-established state with any radio base station other than the own base station as the result of repeating the steps 2 to 9, the controller 51 shifts the process to a step 10.
  • the controller 51 determines whether the own station has been designated as a key station for synchronization (synchronizing key station) or not, and shifts the process to the step 7 when designated, and terminates the processing after setting the synchronization establishing information to ON ("1"). On the other hand, when it is determined in the step 10 that the own station is not designated as a synchronizing key station, the controller 51 terminates the synchronization processing while maintaining the synchronization establishing information to an OFF ("0") state without shifting to the step 7.
  • any radio base station called as a radio base station B which is not designated as a synchronizing key station receives a broadcast signal from another radio base station called as a radio base station A which is in a multizone state with the base station B and designated as the synchronizing key station
  • the radio station B executes synchronization with the synchronizing key station A.
  • Another non-synchronizing key station called as a radio base station C which is in a multizone state with the radio base station B, which is synchronized with the synchronizing key station A, executes synchronization with the radio base station B upon receiving the broadcast signal transmitted from the radio base station B.
  • synchronizations of peripheral radio base stations with the synchronization base station A are performed successively one after another.
  • correction of synchronization deviation is made by using radiowave propagation time at an average distance among a plurality of base stations forming a multizone or propagation delay time of radiowave between adjacent base stations which was obtained in advance and stored in a memory.
  • accurate propagation delay time of radiowave between the base stations is obtained in place of the propagation time of radiowave at an average distance among the base stations.
  • the propagation delay time required for the radiowave emitted from a certain base station to reach an adjacent base station is normally several hundred ns to several ⁇ s.
  • the propagation delay time of this order is negligibly small as compared with a transmission speed of control data of a typical mobile radio communication system.
  • the transmission speed of the control signal is 384 Kbps (period: approximately 2.6 ⁇ s). Since 100 meters to 200 meters are assumed as the cell radius in this case, the propagation delay time between adjacent base stations is approximately 0.33 ⁇ s to 0.66 ⁇ s.
  • the control of transmitting power at a base station has a tendency to become still more complicated in consideration of effective utilization of frequencies, accommodation of handover function to a high-speed moving carrier and the cell radius of a microcell (in other words, an average receiving level of radiowave) changes dynamically depending on conditions such as traffic and site factors and selection of the frequency to be utilized and is not constant.
  • a system in which large-cell converage zones (macrocells) each having a radius of 1 Km to 15 Km corresponding to an existing car telephone system and microcells are mixed (overlaid) has been proposed.
  • the synchronization error produced by the propagation delay time or the like, which is not compensated completely is larger than the synchronization error produced by fluctuation of the frame length between the base stations, which is derived from frequency deviation of a crystal oscillator in each base station.
  • the propagation delay time is measured using a common control channel f1.
  • Suffixes T and R added to f1 in the figure indicate uses for transmission and reception, respectively.
  • previous arrangements are made as to the frequency f1 of the control channel used for the measurement of the propagation delay time between the base stations such as a predetermined slot of the broadcast signal and the communication steps of procedure prior to commencement of the measurement of the propagation delay time.
  • the base station A is in the synchronization established state, and the base station B executes synchronization with the base station A.
  • a unique word (UW) included in the broadcast signal transmitted from the base station A is detected by the base station B with a delay of ⁇ 1.
  • the base station B starts transmission of a broadcast signal including a unique word at a lapse of a predetermined period of time ⁇ 2 after detecting the unique word transmitted from the base station A, and this broadcast signal is detected by the base station A with a delay of the propagation delay time ⁇ 1.
  • the base station A transmits a broadcast signal including the unique word to the base station B again at a lapse of predetermined time after detection of the unique word.
  • the base stations A and B are operated by the same hardware and software. In this case, the time ⁇ 2 from detection of the unique word included in the received broadcast signal to start of transmission of a next broadcast signal and the time ⁇ 3 from start of transmission of the broadcast signal to end of transmission of the unique word are not different between the two stations.
  • the time T B from the base station B detecting the unique word transmitted from the base station A to the base station B again detecting the unique word is obtained by referring to Fig. 6, as follows.
  • ⁇ 2+ ⁇ 3 may be regarded as a constant value when the jitter or the like is neglected.
  • the propagation delay time is measured at the base station A in place of the base station B, and the results of measurement are informed to the base station B utilizing an appropriate control channel.
  • T A the time interval from a time when the base station A terminates transmission of the unique word to a time when the base station A detects the unique word transmitted from the base station B
  • ⁇ 1 T A /2 - ( ⁇ 2+ ⁇ 3)/2
  • the system may be structured so that average values of T B and T A covering a plurality of frames are measured by repeating the communication sequence of the broadcast signal including the unique word in a plurality of times consecutively, and the propagation delay time ⁇ 1 is calculated from the expressions (2) and (3) based on the average values of T A and T B .
  • the propagation delay time ⁇ 1 is calculated from the expressions (2) and (3) based on the average values of T A and T B .
  • ⁇ 2 differs depending on the radio base station due to the differences of software and/or hardware, between the radio base stations, it may be structured so that a value of ⁇ 2 in each base station is informed to an adjacent radio base station while including the value in a control signal or the like.
  • Fig. 7 shows another example of a method of measuring a radiowave propagation delay time.
  • Fig. 7 two control channels of appropriate frequencies f1 and f2 are allocated in advance to the communication sequence for measuring the propagation delay time, and these control channels are used alternately.
  • this method although it takes time for switching the control channels, it is possible to measure the propagation delay time in a similar manner to the case shown in Fig. 6 by setting the value of ⁇ 2 including the time required for switching.
  • Fig. 8 is a typical diagram showing a structural example of service areas of a mobile radio communication system according to the present invention.
  • a lower rank exchange 301 such as a PBX and a terminal exchange and mobile radio communication control stations 302 and 303 are connected to a higher rank exchange 110 through communication lines 341, 342 and 343.
  • the higher rank exchange 110 is connected further to a higher rank exchange network through a signal line 340.
  • the radio base stations 201 to 205 such as telephone sets belonging to respective houses and public telephone sets accommodated in the lower rank exchange 301 through signal lines 26 (including signal lines 29 in Fig. 2 and signal lines 28 in Fig. 3) are arranged while forming multizones mutually including the other radio base stations in respective service zones 201a to 205a thereof.
  • a radio base station 206 accommodated in the lower rank exchange 301 includes no other radio base station in a service zone 206a thereof.
  • radio base stations 207 to 213 accommodated in the mobile radio communication control station 302 through the signal lines 26 are arranged while forming multizones mutually including other radio base stations in respective service zones 207a to 213a thereof.
  • radio base stations 214 and 215 connected to the mobile radio communication control station 302 include no other radio base station in respective service zones 214a and 215a thereof.
  • a service zone 216a is that of a radio base station 216 accommodated in the mobile radio communication control station 302 which is installed later.
  • radio base stations 220 to 222 accommodated in the mobile radio communication control station 303 through the signal lines 26 are arranged while forming multizones mutually including other radio base stations in respective service zones 220a to 222a thereof.
  • the radio base station 222 is arranged in a state that the radio base station 205 accommodated in other lower rank exchange 301 is included in the service zone 222a thereof.
  • no other radio base station is included in a service zone 223a of a radio base station 223.
  • the radio base stations 201 to 205 and the radio base station 222 in a multizone state with contiguous zones are synchronized with a synchronizing key station included in them appropriately.
  • the radio base stations 220 and 221 in a multizone state mutually are synchronized with each other, and the radio base stations 207 to 213 in a multizone state mutually are also synchronized with one another.
  • the radio base stations 206, 214, 215 and 223 which are not in a multizone state with any of adjacent base stations are operated in an asynchronous state with other radio base stations.
  • a telephone set with a child set (a PHP) is newly installed in this state as the radio base station 216 accommodated in the mobile radio communication control station 302.
  • This newly installed radio base station 216 forms a multizone with the adjacent radio base station 213 which has been already shifted to a synchronized state, and is shifted to a synchronized state with the radio base station 213 when receiving a broadcast signal from the radio base station 213.
  • the radio base station 214 is shifted to a synchronized state with the radio base station 216 when a broadcast signal is received from the radio base station 216 which has shifted to the new synchronized state.
  • the peripheral radio base stations which form a multizone with this station 216 are shifted successively one after another.
  • the key station executes synchronization upon receiving the broadcast signal transmitted from another key station which is in the synchronized state or another synchronizing non-key station which is synchronized with the synchronizing key station which is in the synchronized state so that the key station is again shifted to the synchronized state through the synchronized key or non-key station.
  • the process is proceeded to the step 12, and it is determined whether the priority of the receiving base station is higher than the priority of the transmitting base station or not.
  • the process is proceeded to the step 7.
  • the priority of the receiving base station is lower than the priority of the transmitting base station, the process is proceeded to the step 6 and the receiving base station establishes synchronization with the transmitting base station.
  • synchronization is established at a lapse of a certain period of time by having the synchronizing key station in the independent service zone synchronized with the synchronizing key station of the original service zone in advance or by inverting the synchronization establishing information of all the radio base stations within the independent service zone from ON ("1") to OFF ("0").
  • multi-stage priorities i.e. a plurality of different degrees of priority for key station may be allotted to the respective radio base stations and the degree of the priority allotted to each transmitting radio base station is included in the synchronization establishing information included in the broadcast signal transmitted from the transmitting radio base station.
  • the receiving radio base station compares, in the step 4, the degree of priority indicated by the synchronization establishing information included in the broadcast signal which the receiving radio base station has received with the degree of priority allotted to the receiving radio base station.
  • various structures described below are applicable for shortening the period of time required for synchronization establishment between radio base stations. Those are: a structure that, while a plurality of carriers are allocated to a normal broadcast signal, the period of time required for the radio base station on the receiving side to detect the received broadcast signal is shortened by allocating a specific carrier among those carriers to the broadcast signal utilized for synchronization establishment; a structure in which only a specific radio base station such as a synchronizing key station transmits the broadcast signal for synchronization establishment; and a structure in which a repetitive period of a broadcast signal transmitted for every several frames is set to the minimum repetitive period (such as a period corresponding to a super frame in a PHP).
  • the present invention is applicable not only to the TDMA system, but also to the CDMA system in point of synchronization between base stations in a small zone structure by a digital system.
  • a method of establishing synchronization between radio base stations of the present invention it is structured so that the propagation delay time of radiowaves between adjacent base stations is measured actually and synchronization is established based on the actually measured value.
  • synchronization among respective radio base stations can be realized with very high precision in fluctuation degree caused by the jitter of the transmit-receive equipment in respective radio base stations.
  • a mobile radio communication system of the present invention applied with the method of establishing synchronization described above, synchronization among respective radio base stations which have been brought into a multizone state is established autonomously.
  • a mobile radio communication system including a personal radio communication system or the like for making an interference detecting function and an interference avoiding function effective, and in turn, aiming at effective utilization of frequencies.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)
EP93307951A 1992-10-07 1993-10-06 Verfahren zur Basisstationensynchronisierung und Funkkommunikationssystem mit Anwendung des Verfahrens Ceased EP0592209A1 (de)

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EP0762667A2 (de) * 1995-09-07 1997-03-12 Siemens Aktiengesellschaft Vorrichtung zum Messen der Signallaufzeit einer digitalen Übertragungseinrichtung
EP0777344A2 (de) 1995-11-29 1997-06-04 Telia Ab Verfahren und Gerät zur DECT Netz-Synchronisation
GB2309357A (en) * 1996-01-18 1997-07-23 Nokia Mobile Phones Ltd Private Base Stations
WO1997049201A1 (en) * 1996-06-19 1997-12-24 Northern Telecom Limited Medium access control scheme for data transmission on code division multiple access (cdma) wireless systems
WO1998057448A1 (de) * 1997-06-11 1998-12-17 Siemens Aktiengesellschaft Synchronisation von dect-systemen durch drift der basisstationen
EP0954122A1 (de) * 1998-04-28 1999-11-03 Siemens Aktiengesellschaft Verfahren zum Betreiben eines Funk-Kommunikationssystems und derartiges Funk-Kommunikationssystem
WO1999066663A1 (en) * 1998-06-13 1999-12-23 Samsung Electronics Co., Ltd. State synchronizing method and device of base and mobile station in cdma system
EP1056302A1 (de) * 1999-05-28 2000-11-29 Sagem Sa Verfahren zur Synchronisierung von Basisstationen in einem localen Funknetz und Basisstation dafür
EP1065902A1 (de) * 1999-06-30 2001-01-03 Sagem S.A. Lokales Telefonnetz mit einer Steuerungsvorrichtung für Telefonendgeräte mit einer Kopplungsvorrichtung für zellulare mobile Endgeräte
CN1075703C (zh) * 1994-05-03 2001-11-28 韩国移动通信株式会社 码分多址系统中的反向信道同步方法
CN1086537C (zh) * 1996-07-12 2002-06-19 Ntt移动通信网株式会社 移动通信系统的无线电信道起始传输模式
DE19911480C2 (de) * 1999-03-15 2003-06-18 Siemens Ag Verfahren zur Synchronisation von Basisstationen eines Funk-Kommunikationssystems
EP1936838A2 (de) * 2006-12-21 2008-06-25 Samsung Electronics Co., Ltd. Verfahren zur Synchronisierung von überlappenden Zellen und entsprechendes drahtloses Kommunikationssystem
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JP2600622B2 (ja) * 1994-09-22 1997-04-16 日本電気株式会社 Ｔｄｍａ方式の移動通信システムにおける下り制御信号の送信制御方法
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US6014376A (en) * 1996-09-18 2000-01-11 Motorola, Inc. Method for over-the-air synchronization adjustment in a communication system
JPH10190562A (ja) * 1996-12-26 1998-07-21 Toshiba Corp 移動通信システムの基地局間フレーム同期方式およびこの方式を適用した基地局装置
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JP2000078659A (ja) * 1998-08-28 2000-03-14 Nec Shizuoka Ltd Ｐｈｓ無線移動局
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US6768747B1 (en) * 2000-11-30 2004-07-27 Arraycomm, Inc. Relative and absolute timing acquisition for a radio communications system
US7016325B2 (en) * 2001-01-18 2006-03-21 Strix Systems, Inc. Link context mobility method and system for providing such mobility, such as a system employing short range frequency hopping spread spectrum wireless protocols
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CN101263725B (zh) * 2005-12-27 2012-03-21 富士通株式会社 移动控制装置和越区切换控制方法
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US8010138B2 (en) * 2007-08-15 2011-08-30 Nokia Corporation Alternate mobile network cell synchronization
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CN1075703C (zh) * 1994-05-03 2001-11-28 韩国移动通信株式会社 码分多址系统中的反向信道同步方法
US5784368A (en) * 1994-09-23 1998-07-21 Motorola, Inc. Method and apparatus for providing a synchronous communication environment
GB2293526A (en) * 1994-09-23 1996-03-27 Motorola Inc Providing synchronous communication
EP0732817A2 (de) * 1995-03-15 1996-09-18 Telia Ab Verfahren zur Funksynchronisation in zeitverschachtelten Anordnungen
EP0732817A3 (de) * 1995-03-15 2000-06-07 Telia Ab Verfahren zur Funksynchronisation in zeitverschachtelten Anordnungen
WO1997005722A2 (en) * 1995-07-26 1997-02-13 Nokia Telecommunications Oy Apparatus and method for synchronizing base sites individually in a communication system
WO1997005722A3 (en) * 1995-07-26 1997-03-06 Nokia Telecommunications Oy Apparatus and method for synchronizing base sites individually in a communication system
WO1997007646A1 (en) * 1995-08-15 1997-02-27 Qualcomm Incorporated Method and apparatus for time division duplex pilot signal generation
CN1098611C (zh) * 1995-08-15 2003-01-08 夸尔柯姆股份有限公司 时分双工导频信号发生的方法和装置
AU703396B2 (en) * 1995-08-15 1999-03-25 Qualcomm Incorporated Method and apparatus for time division duplex pilot signal generation
EP0762667A3 (de) * 1995-09-07 1997-11-05 Siemens Aktiengesellschaft Vorrichtung zum Messen der Signallaufzeit einer digitalen Übertragungseinrichtung
EP0762667A2 (de) * 1995-09-07 1997-03-12 Siemens Aktiengesellschaft Vorrichtung zum Messen der Signallaufzeit einer digitalen Übertragungseinrichtung
CN1086077C (zh) * 1995-09-07 2002-06-05 西门子公司 测量一个数字传输装置信号传送时间的设备
EP0777344A2 (de) 1995-11-29 1997-06-04 Telia Ab Verfahren und Gerät zur DECT Netz-Synchronisation
GB2309357A (en) * 1996-01-18 1997-07-23 Nokia Mobile Phones Ltd Private Base Stations
US6381231B1 (en) 1996-01-18 2002-04-30 Nokia Mobile Phones Limited Private base stations
GB2309357B (en) * 1996-01-18 2000-08-16 Nokia Mobile Phones Ltd Communicating between base stations and cellular mobile phones
US5828662A (en) * 1996-06-19 1998-10-27 Northern Telecom Limited Medium access control scheme for data transmission on code division multiple access (CDMA) wireless systems
WO1997049201A1 (en) * 1996-06-19 1997-12-24 Northern Telecom Limited Medium access control scheme for data transmission on code division multiple access (cdma) wireless systems
CN1086537C (zh) * 1996-07-12 2002-06-19 Ntt移动通信网株式会社 移动通信系统的无线电信道起始传输模式
WO1998057448A1 (de) * 1997-06-11 1998-12-17 Siemens Aktiengesellschaft Synchronisation von dect-systemen durch drift der basisstationen
EP0954122A1 (de) * 1998-04-28 1999-11-03 Siemens Aktiengesellschaft Verfahren zum Betreiben eines Funk-Kommunikationssystems und derartiges Funk-Kommunikationssystem
WO1999066663A1 (en) * 1998-06-13 1999-12-23 Samsung Electronics Co., Ltd. State synchronizing method and device of base and mobile station in cdma system
DE19911480C2 (de) * 1999-03-15 2003-06-18 Siemens Ag Verfahren zur Synchronisation von Basisstationen eines Funk-Kommunikationssystems
FR2794332A1 (fr) * 1999-05-28 2000-12-01 Sagem Reseau local de radiotelephonie comportant une pluralite de bases radio et base d'un tel reseau
EP1056302A1 (de) * 1999-05-28 2000-11-29 Sagem Sa Verfahren zur Synchronisierung von Basisstationen in einem localen Funknetz und Basisstation dafür
FR2795898A1 (fr) * 1999-06-30 2001-01-05 Sagem Reseau telephonique local comportant une base de gestion de terminaux telephoniques reliee a des embases de reception de combines de reseaux telephoniques cellulaires
EP1065902A1 (de) * 1999-06-30 2001-01-03 Sagem S.A. Lokales Telefonnetz mit einer Steuerungsvorrichtung für Telefonendgeräte mit einer Kopplungsvorrichtung für zellulare mobile Endgeräte
EP1936838A2 (de) * 2006-12-21 2008-06-25 Samsung Electronics Co., Ltd. Verfahren zur Synchronisierung von überlappenden Zellen und entsprechendes drahtloses Kommunikationssystem
EP1936838A3 (de) * 2006-12-21 2010-05-05 Samsung Electronics Co., Ltd. Verfahren zur Synchronisierung von überlappenden Zellen und entsprechendes drahtloses Kommunikationssystem
US8446893B2 (en) 2006-12-21 2013-05-21 Samsung Electronics Co., Ltd. Enhanced coexistence beacon protocol (ECBP) for precise intercell synchronization of overlapping wireless base stations
WO2010118261A3 (en) * 2009-04-08 2011-04-28 Qualcomm Incorporated Conveying synchronization stratum information
US8774230B2 (en) 2009-04-08 2014-07-08 Qualcomm Incorporated Conveying synchronization stratum information

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